1. Field of the Invention
The present invention relates to an improved sensor that is vibration dampened.
2. Prior Art
In the prior art, a number of devices that combine an elastomeric member with a suitable structural member have been advanced for the purpose of shock isolation or vibration isolation. It has been the object of such devices to prevent the transmission of shock or vibration from one structure to another. The present invention is conceptually remote from such prior art. A device made according to the present invention is designed to dampen the vibration in a structure, the beam, by partially supporting such structure with an elastomeric member held in a rigid supporting second structure, the sheath, in order to reduce the amplitude of vibrations in the first structure. Such use is not known in the prior art. Typical prior art devices, are shown in U.S. Pat. Nos. 3,719,349; 4,187,668 and 4,363,217.
A device made according to the present invention is useful where an elongated beam having an unsupported length is required and such beam is mounted on a structure subject to vibration. In an embodiment, the beam comprises a sensor body that is cantilever in construction. Such a device may comprise for example a temperature sensor in a bleed air duct from an aircraft engine. With a relatively thin beam of steel tube construction and approximately five inches in length measured from the point of mounting to the vibrating structure, it has been shown that a vibrational input equal to six times the acceleration of gravity (6 g's) normal to the longitudinal axis of the sensor body results in acceleration levels at the unsupported end of the sensor body that may reach in excess of 4000 peak g's (4,000 times the acceleration of gravity) at the tip of the sensor body. Normal practice where the beam comprises an elongated sensor body is to dispose the sensor element of the sensor close to the unsupported tip end of the sensor body. Accelerations as indicated above are harmful to such sensor elements and can drastically reduce the useful life of the sensor. Accordingly it is desirable to reduce the effects of the structural vibrations on the sensor body, particularly with respect to the unsupported end of the sensor body. It has been shown that a device made according to the present invention is effective in reducing such accelerations by a factor of up to 20.